Optical packages are typically manufactured using traditional methods that enable optoelectronic chips to communicate with other devices. These traditional methods often include wire-bonding and/or flip-chip packaging processes. These optical packages are generally used in an optical communication system for transmitting and receiving high bandwidth optical signals.
Both optical wire-bond packages and optical flip-chip packages generally include an optoelectronic chip, a substrate and a light energy or radiant energy conducting element such as, for example, an optical fiber or a waveguide. The optoelectronic chip includes an optical element and electrically conductive contacts. The optical element, which may include a transmitter and/or receiver, is generally responsible for transmitting and/or receiving optical signals via the optical fiber and/or waveguide. The optical fiber and/or waveguide is generally adhered or attached to a substrate. Additionally, the electrically conductive contacts of the optoelectronic chip are electrically bonded to a substrate for transmitting and/or receiving electrical signals.
Flip-chip packaging is a proven method for manufacturing optical packages. A flip-chip package may include a waveguide that is adhered to a substrate and that is disposed between an optoelectronic chip and the substrate. During a bonding process, the optoelectronic chip is positioned relative to the waveguide using an active alignment process (i.e., using a sensor, a laser, and a feedback loop) to achieve optimal light or radiant energy signal coupling to the waveguide. The position of the optoelectronic chip relative to the waveguide is limited by the position of the solder pads formed on the substrate. To ensure optimal alignment during the bonding process, the position of the waveguide must be optimally fixed to the substrate relative to the solder pads.
A traditional method of attaching a waveguide to a substrate typically involves using a microscope and a micropositioner to manually align the waveguide to adjacent substrate features such as solder pads. A liquid adhesive is disposed between the waveguide and the substrate and cured to fix the waveguide to the substrate. This method is not well-adaptable for automated processes because the optical alignment tolerance between a waveguide and an optoelectronic chip is +/−5 μm and aligning the waveguide to adjacent substrate features may not meet this tolerance in high-volume manufacturing. Further, using this method, at least two substrate features must be selected to ensure optimal alignment along the X-direction and the Y-direction. The limited viewing range of a microscope typically requires moving the viewing area of a vision recognition system (e.g., a machine vision system) after aligning the waveguide in the X-direction to align the waveguide in the Y-direction, often causing misalignment in, for example, the X-direction.